CVE Intelligence
High Denial of service

CVE-2024-1635 — Undertow: out-of-memory error after several closed connections with wildfly-http-client protocol

A vulnerability was found in Undertow. This vulnerability impacts a server that supports the wildfly-http-client protocol. Whenever a malicious user opens and closes a connection with the HTTP port of the server and then closes the connection immediately, the server will end with both memory and open file limits exhausted at some point, depending on the amount of memory available. At HTTP upgrade to remoting, the WriteTimeoutStreamSinkConduit leaks connections if RemotingConnection is closed by Remoting ServerConnectionOpenListener. Because the remoting connection originates in Undertow as part of the HTTP upgrade, there is an external layer to the remoting connection. This connection is unaware of the outermost layer when closing the connection during the connection opening procedure. Hence, the Undertow WriteTimeoutStreamSinkConduit is not notified of the closed connection in this scenario. Because WriteTimeoutStreamSinkConduit creates a timeout task, the whole dependency tree leaks via that task, which is added to XNIO WorkerThread. So, the workerThread points to the Undertow conduit, which contains the connections and causes the leak.

Published Feb 19, 2024 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: redhat

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 4.6% (30-day exploitation probability)+14
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
4.57%
ahead of 91% of scored CVEs · Oct 14, 2026
Affects
Netapp
Active Iq Unified Manager and 21 more
CVSS base
7.5
High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Maven Io.undertow:undertow-core: fixed in version 2.3.12.Final — github.com (GitHub Security Advisories)
  • Maven Io.undertow:undertow-core: fixed in version 2.2.31.Final — github.com (GitHub Security Advisories)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Netapp Active Iq Unified Manager, Netapp Oncommand Workflow Automation, Red Hat Fuse…).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. Apply the fixed version or the patch documented under Remediation.
  4. EPSS ahead of 91% of scored CVEs: prioritize it in the patch queue.
  5. Search available logs for exploit probes matching the vulnerability class (denial of service), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Netapp Active Iq Unified Manager versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Oncommand Workflow Automation versions not specified by the source Vulnerable NIST National Vulnerability Database
Red Hat Fuse version 1.0 Vulnerable NIST National Vulnerability Database
Red Hat Integration Camel For Spring Boot versions not specified by the source Vulnerable NIST National Vulnerability Database
Red Hat Jboss Enterprise Application Platform version 7.4 Vulnerable NIST National Vulnerability Database
Red Hat Openshift Container Platform version 4.12version 4.11 Vulnerable NIST National Vulnerability Database
Red Hat Openshift Container Platform For Linuxone version 4.10version 4.9 Vulnerable NIST National Vulnerability Database
Red Hat Openshift Container Platform For Power version 4.9version 4.10 Vulnerable NIST National Vulnerability Database
Red Hat Red Hat build of Apache Camel for Spring Boot 4 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat JBoss Enterprise Application Platform 7.1 EUS for RHEL 7 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat JBoss Enterprise Application Platform 7.3 EUS for RHEL 7 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 for RHEL 8 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 for RHEL 9 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 on RHEL 7 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat JBoss Enterprise Application Platform 7.4.16 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat Process Automation 7 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat Single Sign-On 7.6 for RHEL 7 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat Single Sign-On 7.6 for RHEL 8 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Red Hat Single Sign-On 7.6 for RHEL 9 versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat RHEL-8 based Middleware Containers versions not specified by the source Vulnerable CVE Program (cve.org) e CISA ADP
Red Hat Single Sign-on version 7.6versions not specified by the source Vulnerable NIST National Vulnerability Database
Maven Io.undertow:undertow-core ≥ 2.3.0.Final and < 2.3.12.Final< 2.2.31.Final Vulnerable GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.5 CVSS 3.1 High 3.9 3.6 secalert@redhat.com via NIST National Vulnerability Database
7.5 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
7.5 CVSS 3.1 High — — redhat via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: secalert@redhat.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-400 · Uncontrolled Resource Consumption

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 4.57%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Track CPU/memory spikes and availability drops correlated with request patterns.
web/proxy/WAF logsnetwork IDS/IPSresource metrics

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 13, 2026 · GitHub Security Advisories
  • Affected products added · maven/io.undertow:undertow-core
    Oct 13, 2026 · GitHub Security Advisories
  • Affected products added · red hat/red hat jboss enterprise application platform 7.1 eus for rhel 7, red hat/red hat jboss enterprise application p
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 7.5
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • 2024
  • CVE published
    Feb 19, 2024 · redhat

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

21 on the record

Elsewhere on this site

Netapp
every CVE for this vendor
Denial of service
same class
CWE-400
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-104045 Sssd: sssd: denial of service via race condition in autofs responder 9d
  • CVE-2026-104046 Sssd: sssd: denial of service via incomplete identity provider authentication requests 9d
  • CVE-2026-104047 Sssd: sssd: information disclosure via query injection in entra id lookups 9d
  • CVE-2026-104048 Sssd: sssd: authorization bypass via cross-domain username collision in hbac evaluation 9d
  • CVE-2026-90462 Sssd: sssd: fail-open in ldap ppolicy access check allows continued authorization 23d
  • CVE-2026-93574 Io.netty/netty-codec-http: netty: http request smuggling via post-digit whitespace in chunk-size parsing 27d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2024-1635 is "Undertow: out-of-memory error after several closed connections with wildfly-http-client protocol", rated High. It affects Active Iq Unified Manager (Netapp); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 4.57% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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